GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi my name is ***** ***** I will be happy to assist with this today.I need a little more info to assist better.
Is this the heater air that comes out that isn't warm at idle or the engine temperature?
Let me know so we can continue,thanks Pete.
Is the actual engine temperature reaching 240 degrees F at idle?
O.k.,this is an over heat issue.Your engine should not get any warmer then 210 to 220 at the most in extreme heat conditions.I suspect either the fan clutch is the cause needing replaced,radiator fins are bent/damaged,restriction with the coolant system or an issue with a cylinder head gasket leak causing exhaust heat/gasses to enter the cooling system causing an overheat issue.These all need checked into to locate which is the cause here then repaired from there.
If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Thanks Pete.
This test is done with what is called a block tester.This tester can usually be purchased at places like Napa or other parts and tool stores.Almost all repair shops have this tool as well to test this.The test usually takes around an hours time to test.Auto Zone also carries it. http://www.autozone.com/loan-a-tools/block-tester.It will come with easy to follow instructions to do this testing.If the block test comes back negative and there is no head gasket leak (this leak would be where the exhaust heat and gasses leak into the cooling system and won't show up as an external leak of oil or coolant or oil mixing with coolant) then I would have the engine flushed as there can be restriction in coolant flow causing this here.
I apologize for the delay.
The only other thing I see that will cause this here is a restriction in the engine coolant system or possibly that the engine coolant temp sensor is sending a false temp signal needing replaced.If you haven't had a coolant flush done I would see if this corrects this issue and if this is done or is o.k. I suspect you may have a faulty engine coolant temp sensor causing this needing replaced.
Does the ac condensor have any air flow restrictions that may be blocking the air from flowing through the radiator properly when the fan clutch engages?